Results from our ongoing NIDCD-funded study in Tanzania in show that the main auditory problems in HIV+ adults and children are in the central nervous system. These deficits likely develop for the same reasons as HIV associated neurocognitive disorder (HAND) (i.e. due to effects on central nervous system pathways). These data also suggest that audiological tests of central auditory processing may be useful tools to study and track the effects of HIV infection and HIV treatment on the central nervous system. But, no data exist that correlate the results of audiological tests of central auditory processes and standard measures of cognitive function. Also, it is not known if these tests would be more sensitive or provide earlier detection of neurological complications than existing tests. Since these audiological tests are often well-standardized and easy to perform, they may offer improved ways to detect neurological dysfunction in HIV+ patients. The objective of the proposed study is to assess central auditory processing (e.g. gap detection thresholds, speech-in-noise thresholds, staggered spondaic word test results, and complex auditory brainstem response) in an established, well-studied, cohort of HIV+ and HIV- adults and children at the Infectious Disease Center in Dar es Salaam, Tanzania. The results from the auditory tests will be correlated with results from cognitive testing (T.O.V.A. and Cogstate batteries) as well as inflammatory marker levels (IL-6, sCD14), and followed over time. The combination of the audiological testing protocol with neurocognitive test results and inflammatory marker levels--all followed longitudinally--will provide a powerful combination to assess the appearance and progression of central neurological complications over time. Our study will use a laptop-based hearing testing system that includes: native-language questionnaire administration to assess self-reported hearing capability and exposure to noise, drugs and toxins; threshold audiometry to assess overall hearing ability; adaptive gap detection testing to measure temporal processing; speech-in-noise testing in Kiswahili to assess speech perception; tympanometry to determine middle ear status; staggered spondaic word testing in Kiswahili to assess binaural speech processing. Complex auditory brainstem response measures to assess auditory processing will be done with a dedicated commercial evoked potential system (Smart-EP). HIV- and HIV+ adults and children will be enrolled, and studied longitudinally with both a central-auditory- processing-focused protocol and tests of neurocognitive function using the T.O.V.A. and Cogstate test battery. Plasma will be collected for analysis for sCD14 and IL-6. The combination of the hearing testing systems with the research-experienced, high-volume clinic in Tanzania, will provide an excellent environment to confirm and expand knowledge about the central auditory processing deficits in HIV infection, and ascertain how these findings are related to neurocognitive findings and inflammation.